1. Field
The embodiments described herein relate generally to particle accelerators. More particularly, the described embodiments relate to particle accelerators capable of providing a plurality of radiation dose rates.
2. Description
A particle accelerator produces charged particles having particular energies. In one common application, a particle accelerator produces a radiation beam used for medical radiation therapy. The beam may be directed toward a target area of a patient in order to destroy cells within the target area by causing ionizations within the cells.
A conventional particle accelerator includes a particle source, an accelerator waveguide and a microwave power source. The particle source may comprise an electron gun that generates and transmits electrons to the waveguide. The waveguide receives electromagnetic waves from the microwave power source, which may comprise as a magnetron or a klystron. The electrons are accelerated through the waveguide by oscillations of the electromagnetic waves within cavities of the waveguide.
The accelerating portion of the waveguide includes cavities that are designed to ensure synchrony between electrons received from the particle source and the oscillating electromagnetic wave received from the microwave power source. More particularly, the cavities are carefully designed and fabricated so that electric currents flowing on their surfaces generate electric fields that are suitable to accelerate the electron bunches. The oscillation of these electric fields within each cavity is delayed with respect to an upstream cavity so that a particle is further accelerated as it arrives at each cavity.
A conventional particle accelerator may output particles at a particular dose rate that depends upon, among other factors, the electron current received from the particle source and the power of the electromagnetic wave received from the microwave power source. A different dose rate may be achieved, in some instances, by varying the electron current and the power of the electromagnetic wave. However, varying these factors may cause an undesirable change in the value of the energy of the output particles.